A glint is the reflection of a light source off from an object. For example, when light from a light source reflects off from someone's eye, a glint can be detected in an image captured by a camera. The glints can be analyzed to perform such functions as determining 3D geometry of the object. If the object is a person's eye, it is possible to determine a 3D vector that describes a direction in which the person is gazing. There are many other applications of analyzing glints, such as object recognition, high speed motion tracking, and production line control.